MongoDB syslog isn't working on OSX?

[Pablo Cantero]

Hello

Do I need to some more to enable `syslog` on MongoDB 2.4.9 running on OSX 10.9.1, besides enabling it in the `mongodb.conf`?

$ mongod

$ using syslog ident: mongod.27017

Although it seems to be working when I started  the `mongod` process, I couldn't find any mongo long in my `/var/log/syslog.log`.

Thanks

[Greg Donald]

`man syslog` seems to imply the default path is /var/log/system.log,
and that's what I'm seeing when I issue a generic syslog command.

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Greg Donald

[Stephen Steneker]

Hi Pablo,

It looks like you need to set up some extra rules for syslog in OS X 10.9.1 (I haven't tried on any earlier versions yet). The syslog messages are processed via the ASL (Apple System Log) facility.

I was able to get this working with MongoDB 2.4.9 by adding a new file "/etc/asl/org.mongodb" and matching messages with the syslog ident (mongod.27017). You don't have to call your file "org.mongodb", but it is consistent with the other files that are there. You will have to use `sudo` to create/edit any files in the /etc/asl/ directory.

A few example rules I tested in my /etc/asl/org.mongodb config:

# Log all messages via syslog to a separate mongodb.log
? [= Sender mongod.27017] claim only
* file /var/log/mongodb.log mode=0640 compress format=bsd rotate=seq file_max=5M all_max=20M

# Save all messages to system.log
? [= Sender mongod.27017] file /var/log/system.log

After you change the rules file, you need to send a HUP signal to syslogd:

ps -ef | grep -i '/usr/sbin/syslogd' | awk '{print $2}' | head -1 | xargs kill -HUP

There may be some additional rule tweaks needed but this should be a good starting point.

I would also note that messages to syslog in MongoDB 2.4 do not include stack traces (eg. as are sometimes printed by assertions). These stack traces can be informative for troubleshooting and problem diagnosis. FYI, the logging behaviour has been improved in the MongoDB 2.5 development/unstable releases (see SERVER-8825 and related tickets).

Regards,

Stephen

[Pablo Cantero]

Hello

Thanks for both replies! Problem solved. :)

I created the `/etc/asl/org.mongodb` and it worked like a charm. 

It is something that I only needed in the development to use the log rotation, because last time I saw my `mongo.log` was occupying 9GB.

Thanks again